1. Field of the Invention
The present invention relates to a feed roller for feeding and guiding a paper, fabric or cloth web from an intake portion to a working portion. More particularly, the present invention relates to a web feed roller adapted for a rotary press in which a rolled paper web is moved at high speed from a paper reservoir section to a folding section through a printing section and the web feed roller is driven in the same direction of the web travelling direction. Furthermore, the present invention relates to a drive control system associated with the above defined web feed roller.
2. Description of the Prior Art
In recent years, printing systems, especially those used in a newspaper printing company, have required a compact and high speed rotary press which can perform printing work at a high speed and can provide much printed material within a limited space. Furthermore, newspapers include much information and thus have often expanded and enriched their pages and color printing sections. This requires complicated printing systems. For example, printing works have been increased for each page, and paper web guiding processes have been complicated and may be varied in many ways. According to these complicated printing systems, the web travelling distance has been extended to require many guide rollers. Under this condition, if the rotary press is driven at an extremely high speed, the paper web will suffer a high tension load.
On the other hand, the paper web required has been gradually changed to be thin and light for satisfying the need that winding length of each rolled web should be extended for low cost performance and compact size; that the interval of connecting section between two rolled webs be extended as much as possible to reduce paper loss and the non-working period of printing system, and that the whole thickness of newspaper should be thin regardless of increment of pages.
The high speed rotary press and such thin and light paper web also requires changes to ink characteristics. If conventional ink is used in this high speed rotary press, the printed ink will not be completely dried. Thus, wet-ink will adhere on the surface of the feed or guide roller for feeding or guiding the printed web. Furthermore, paper dust will be also deposited on the ink adhered to the surface. The adhered ink and deposited paper dust will spoil the printed surface and provide travelling stress to the paper web. This travelling stress will sometimes cause tearing of the paper web (refer to "Supplement Edition Printing Dictionary" published and edited by Japan Printing Academy Corporation; the first edition on Jun. 30, 1987; page 74, item "Guide Roller Spoiling").
Therefore, such conditions require a decrease in the tension load applied to the paper web travelling through the rotary press. In other words, many guide rollers, or all guide rollers in the rotary press, as required, should be driven to control the tension load applied to the travelling paper web.
Conventionally, the guide rollers in the rotary press are not connected to drive means as disclosed in "Guide Roller" on page 74 of "Supplement Edition Printing Dictionary". However, if the rotary press is driven at a high speed, such non-driven guide rollers will cause problems. For example, the paper web travelling in front of the paper feed roller will be bent or loosened; or the travelling speed of the paper web will directly depend on printing speed or inertial force of the guide roller.
A drag roller, a driven roller arranged on a guide way for the paper web travelling through the rotary press, is well known. Such a drag roller is driven at a slightly faster speed than a printing plate cylinder to always apply tension on the paper web, as referred to in the disclosure on page 61, line 23 to 27 in right column of "News Paper Printing; Printing Art, Reversed Edition" published on Oct. 31, 1980 by Nippon News Paper Association Corporation. This drag roller is driven by a main power source of the rotary press through a lot of gears as shown in FIG. 57 on page 48 of "News Paper Printing; Printing Art, Reversed Edition".
In addition to the above problems, a printing system has been enlarged by connecting many rotary presses and driven at a high speed. This enlarged printing system will also cause to an increase in the tension load applied to the paper web travelling along the guide way of this printing system. Thus, this tension load will sometimes generate defects in product quality and make working efficiency poor. To overcome these defects, some driven rollers in addition to the drag roller have been arranged on the guide way as disclosed in Japanese Patent Laid-Open Publication No. 51-137508 (Japanese Patent Publication No. 58-30217) entitled "Tension Control Device for Running Paper in Rotary Press" Japanese Utility Model Laid-Open Publication No. 53-13802 (Japanese Utility Model Publication No. 56-4595) entitled "Tension Adjusting Device for Paper Running along Paper Feed Way in Rotary Press", and Japanese Patent Laid-Open publication No. 52-136010 entitled "Tension Control Device in Rotary Press".
In these references, the driven roller arranged on the paper guide way includes a roller shaft rotatably supported on a frame of rotary press, and a gear drive means secured on one end of the roller shaft. The gear drive means is mechanically connected to a driving source isolated from the driven roller. However, this driving system requires an additional driving unit for driving and control of the driven roller. Thus this driving system is more complicated and larger in scale and requires a relatively wide space for positioning. Accordingly, the driven roller can not be positioned in an area where many elements or parts are gathered such as, for example, the inlet portion of folding section where many guide rollers are closely arranged. Furthermore, this complicated and large scale system requires hard work and considerable cost to assemble and maintain. Also, such a complicated and large scale driving system causes loss in driving efficiency.